Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1131 AM EST Sun Feb 02 2020 Valid Feb 02/1200 UTC thru Feb 06/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation with Latest Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ ...Deep longwave trough evolving over the Western U.S. this week... ...Surface wave activity developing over the lower/mid MS Valley... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ Preference: Blend of the 00Z non-NCEP models and 06Z GEFS/00Z ECENS means Confidence: Slightly above average The 12Z GFS and to an extent the 12Z NAM just as it in previous runs continue to be more progressive with the evolution of the deep longwave trough evolution over the Western and Central U.S. over the next few days. This drives a more progressive surface wave evolution over the lower MS Valley and eventually the Gulf Coast states by late Wednesday, with the GFS in particular outrunning the guidance. The ensemble means led by the 06Z GEFS and 00Z ECENS suites favor the less progressive consensus led by the 00Z non-NCEP (UKMET, CMC and ECMWF) solutions. Will continue to favor a non-NCEP blend along with the latest ensemble means. ...Northern stream energy traversing the northern Plains/Great Lakes... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ Preference: Blend of the 00Z non-NCEP models and 06Z GEFS/00Z ECENS means Confidence: Slightly above average There are subtle differences with respect to a northern stream trough clipping the northern Plains, Great Lakes and northern New England through Wednesday, but the 12Z NAM/GFS solutions do tend to be more out of tolerance with the non-NCEP solutions and the latest ensemble means. Will continue to favor a non-NCEP consensus with this energy as well given the better clustering/ensemble support toward this camp. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Orrison